How do homopterans damage fruit trees and grain crops?

Homopterans are plant-feeding insects that damage fruit trees and grain crops primarily by sucking sap from their hosts. This feeding behavior causes several types of injury:12

• Physiological Damage: Insects like leafhoppers interfere with plant physiology by removing excessive sap and destroying chlorophyll, leading to yellowing, browning, and stunted growth. Some secretions cause cell hypertrophy that impairs sugar transport, resulting in "hopper burn" and potential crop loss.1
• Physical Destruction: Egg deposition slits made by cicadas in green twigs weaken limbs, causing them to break under the weight of fruit. Similarly, scale insects can encrust bark and limbs, often killing the entire plant.1
• Disease Transmission: Many homopterans act as vectors for plant disease viruses and bacteria, including fire blight, corn stunt, and various mosaic diseases.1
• Honeydew and Sooty Mold: Surplus sap is excreted as honeydew. When this falls on fruit, it promotes the growth of sooty mold, which blackens the produce and renders it unmarketable.1

Would you like to know more about the specific biological methods used to control these pests?